3D printing lunar regolith simulant with microbial-carbonated magnesium oxide

Lunar construction is important and a challenge for building space habitation. Several technology routines using in-situ lunar regolith as the base material for making lunar bricks have been proposed but they are still waiting in the list of verification. In this study, a new additive manufacturing method for making lunar regolith structures with biocarbonated magnesium oxide (MgO) was proposed. A lunar regolith simulant (LRS) was prepared. The effects of microbial-based prehydrolyzed urea solution, additives, and aggregates, on the properties of 3D printing mortars were investigated. The compressive strength and microscopic images of 3D printed specimens were analyzed. The test results showed that the microbial-based mortar has significantly different flowability and buildability compared with water-based mortar. The compressive strength of 3D printed specimens can be improved several times with the biocarbonated method. Microscopic images showed that the printed biocarbonated specimens show denser structure and more magnesium carbonate hydrate, causing the improvement of mechanical behavior. Complex LRS-based structures were printed with the biocarbonated magnesium oxide method, which can bear a certain of loads.